The present invention is generally directed to compressed air systems, and more particularly to apparatus for removing moisture from compressed air, prior to use.
In today's modern manufacturing and assembly plants, pneumatically operated tools and pneumatically controlled machines are used extensively. These machines and tools are, for the most part, expensive and subject to corrosive damage occasioned by the presence of moisture in the compressed air operating systems. This corrosion and rusting, in part, results in excessive maintenance and ultimate replacement. Further, the operation of sensitive pneumatic instruments and controls, coupled to these systems, is materially affected by excessive moisture in the air. In addition to the corrosive action, the water vapor often will contain numerous impurities and contaminants such as oil, dust and pipe scale that can and do produce harmful results upon condensing of the water vapor.
So long as the water vapor remains in suspension, there is little danger of damage in moist compressed air systems. It is only when the water vapor condenses to produce free water, that damage occurs.
Numerous forms of air dryers have been proposed and are presently in use. One example is the absorbent type of air dryer which employs a large chamber or tank within which a dessicant is stored. The compressed air is passed through the tank, prior to being supplied to the air line, with the dessicant absorbing a considerable amount of vapor. However, the operating and recharging costs of this type of air dryer are high.
Another form of air dryer which has found considerable use in such systems is a refrigerated air dryer. One such refrigerated air dryer system is fully disclosed in U.S. Pat. No. 3,722,583, which issued on Mar. 27, 1973 to the assignee of the present invention. In this type of dryer, the relatively hot compressed air is brought into contact with a refrigerant carrying coil to lower the air temperature and produce condensation of the water vapor, which is then collected in a moisture separater. Most importantly, this type of air dryer is capable of lowering the dew point of the air, such that there is little or no chance of subsequent condensation occurring. While this type of air dryer has been found to be quite effective for removing moisture from compressed air prior to use by pneumatically operated machinery, there remains room for improvement. For example, the system disclosed in the aforementioned patent contemplates that a moisture separater be employed downstream from the refrigerant carrying coil for separating the condensed moisture from the air to be dried. In practice, it has been necessary to connect the air cooling portion of the system to the moisture separater by a tubing which, usually of necessity, must be provided with bends along a rather circuitous route to the moisture separater for conveying the cooled air to the moisture separater. The rather circuitous route of the tubing results in a considerable amount of agitation of the cooled air with the result that a significant portion of the condensed moisture is re-evaporated into the cooled air and is not collected by the moisture separater. As a result, at least some moisture remains in the air which is utilized by the pneumatically controlled machinery. This of course, as stated above, it undesirable.
It is therefore an object of the present invention to provide a new and improved air dryer system.
It is a more particular object of the present invention to provide an air dryer system which is considerably more effective in removing moisture from compressed air to be utilized by pneumatically controlled and operated machinery.
It is a still further object of the present invention to provide a new and improved refrigerated air dryer system which includes a moisture separater connected directly to the air cooling portion of the system to thereby eliminate the need for long expanses of coupling tubing between the air cooling portion of the system and the moisture separater.